Communications

The field of communication involves the transmission of information from one place to another place or storing information for later retrieval. A communication system is a pair of stations - a transmitter station and a receiver station. Communication networks are collections of receiving and transmitting stations that may relay information from one station to another by means of other stations acting as relays. There are many components in the process of transmitting information in a communication system. One component is information representation in minimal form, that is data compression. A second aspect of communication is modulation; the process whereby information is mapped into waveforms suitable for propagation. A third aspect is error control coding; the method by which errors made in receiving information can be corrected. The performance of a communication system is usually measured in terms of the probability of incorrectly decoding the information or the distortion between the original information-bearing signal and the reconstruction, and the energy used. In communication networks there are many components needed in the processing of sending information from one station to another via a set of intermediate stations. One aspect is medium access control - meaning which stations should transmit and when. Another aspect of communication networks is routing - meaning which set of stations should be used as relays in communicating information from one station to another station. The performance measures in communication networks are the network throughput (correctly decoded packets end-to-end) along with the energy consumed.

Communications research at U-M is investigating the fundamental limits of performance possible in communication systems and communication networks and the practical methods of achieving close to the fundamental limits. The applications that are of interest include cellular communication networks, sensor networks, and optical communication systems.